Differential gearing.



H. M. PATCH.

DIFFERENTIAL BEARING.

APPLICATION FILED DEC. 4. 1915.

1 ,259,??9. Patented Mar. 12, l9l&

2 SHEETS-SHEET I.

' INVEA TOR /7( M fi rcH ATTORNEY M. Pl H.

ERENT ARING.

TlON .4.19:5.

Patented; Mar. 12, 1918.

2 SHEETS-SHEET 2.

4 TTORA/E V BIFFERENTIAL GEARING.

Specification of Application filed December 4, 1915. Serial No. 64,964.

To all whom it may concern:

Be it lznown that I, HARRY Ml PATCH, a citizen of the United States,residing at Seattle, in the county of King and State of Washington, haveinvented certain new and useful Improvements in Diil'erential Gearing,of which the following is a specification.

This invention relates to improvements in dii'l ercntial gearing forautomobiles, and

has for its object the prov'sion of mechanism of simple construction forequalizing the rotative speed of the driving wheels and to prevent themotive power from being applied to rotate one wheel faster than theother.

The invention consists in the novel con struction, and combination ofparts of an "automobile. differential gearin as will be fully describedin the following specification, illustrated in the accompanying drawingsand finally set forth in the appended claims.

In said drawings, Figure 1. is a view in horizontal section of apparatusembodying my invention. Fig. 2 is a vertical section on line 2-2 ofFig". 1. 3 is a vertical section throughthe center of the rotatablehousing: as illustrated in I. Fig. 41 is a view in horizontal section ofan cmbodimerit of my invention in somewhat modified form. I

Referring to Figs. 1, 2 and 3 of said views, the reference numerals 5and 6 indicate the inner ends of a divided wheel-axle of an automobilewhich ends are squared. as at? and 8, upon which relatively oppositclyfaced gear-wheels 10 and. 11, to be hereinafter morespecificallydescribed, are respectively mounted.

Said gear-Wheels are each formed with outwardly disposed hubs 12 withwhich a divided housing 13 is rotatively associated, said housingmmprisinp the two sections 15 and 16 which are connected by bolts 17which also serve to connect therewith the mastengear 18 through whichsaid housing may be driven by the motor (not shown) through the meshingpinion 20 and powershait 21.

A plurality of pinions, as 22, are mounted upon spindles 23 supported inbearings 25 and spaced symmetrically within the housing 1 Said pinionsare provided with teeth 26 of special form in mesh upon opposite sidesWithin the convolutions of the Letter Pat n Paton ted Mar. 12, 1918.

gear-wheels 10 and 11 and adapted to be driven by the latter when eitherof'wheelaxles 5 or 6 are rotated at a greater speed than the housing 13.

Referring particularly to Fig. 2, the gearwhcels IO and 11. as nowconsidered, are provided-with teeth 27 oi: convolute config uration.raised upon their relatively opposed faces, the outermost portions ofsaid teeth with which the pinion-teeth engage having-a relatively slightangular pitch; that is to say, at approximately twelve degrees angularadvance. whereby said pinions may be driven in either direction by therotative movements of the gear-Wheels but the lat ter may not beiflriven in their turn by the rotation 01" the pinions. In effect, saidgean wheels act upon the pinions in the manner of a woman whose pitchinclination-prevents its being back-driven by its inl'crmcshingworm-gear.

The gear-wheels 10 and 11 have the convolutions of their respectiveteeth 27 cut in opposite directions so that when arranged in operativeopposed relation, the teeth of both gear-wheels extend in similardirections.

The teeth 26 of said pinions are shaped to conform to the curvature ofthe spaces between the teeth 27 of ihe geanwheels and are of similar andsymmetrical configura tion in order that they may be similarly actedupon by the respective opposed teeth of both gear-wheels. That is tosay, upon each side of a tooth an intermediate concave portion 28 isformed, adapted to he engagged by the outer convex side of a teeth 27tending to drive the proximate side of the pinion in outward directions.and a convex portion 29 at that end oi each said tooth extending; in thedirection toward the convergingcouvolutions adapted to be engaged by theinner concave side of a tooth 27 and tending to drive the proximate sideof the pinion iii inward directions.

When the vehicle is driven upon the straight course. the gear wheels 10and 11 are driven with the housing and the axles 5 and 6 at the samespeed, and the pinions 22 are motionlcssupon their axes. When rounding acorner, one axle section runs ahead and the other axle section runsbelow the housing speed. By observing Fig. 1 it 'will be seen that ifrounding a corner with the section 5 outside, such section is compelledto rotate more rapidly than the secuse tion 6, with the result that thegear memscribed. When one veiiicle wheel loses traction, it cannot bedrivenby the motor faster than the other'wbeel or caused to spin, as norotation can be imparted to the geanwheels by the rotation of thepinions upon their oWn axes.

I am aware that other devices for equalizing the speed of the drivingWheels of automobiles have been utilized, which embody right and lefttoothed gear-Wheels in'termesh' ing with doublothreadod woiins mountedin a rotatable housing, wherein the Worms are actuated by one Worm-gearto rotate the opposite Worm-gear, as shown and described in patent toGraham, No. 1,112,422. In my invention, it is essential that-the pinions22 shall prevent the transmission of motion from one gear-Wheel to theother, except through the housing, and by rotation of said pinions aboutthe of the gear-Wheels whereby one vehicle wheel cannot be driven fasterthan the other through loss of traction.

In Fig. 4 I illustrate a modified form of my invention, wherein theWheel axle 5 and 6 are provided with worms 10 and 11 having threads 30of relatively opposite pitch.

1 Worm-pinions 22 are operatively engaged with said worms and arerotatively mounted in the housing 13 in a manner analogous to thepreviously described construction.

The angular pitch of the threads 30 are such that the worms 10 and 11Will readily rotate the worm-pinions 22" upon their axes, but the Wormsmay not be actuated by the rotation of the '\VO'IIH-}JlHiOIIS11PO11their but only through their rotation around the axes of the Worms.

Having described my invention, What I claim, is

1.111 differential gearing, a rotatable housing, a pinion mounted forrotation in said housing, a pair of gear Wheels in relatively oppositerelation having teeth in mesh with said inion, the teeth of the pinionbeing roun ed at one end and pointed at the other, with the oppositefaces thereof concaved, the teeth of said geanwheels having a relativelyopposite angular pitch of relatively slight aevs angular advance wherebyrotary motion from one sai l 8&1V'Vl188l to the other b the rotation ofsaid pinion about its axis, is prevented, the rotation being permittedby the rotation of said pinion about the axes of the gearuvheels,

in. differential gearing, a driven housing, a pair of alined axlesrotatably mounted axially of said housing, geanwheels fixedly secured tothe inner ends of said axles having-tooth of relatively opposite angularpitch, a pinion rotatively mounted in said housing; having teethintermeshing with both said gear-Wheels, thatceth of th pinion beingrounded at one end '1 pointed at the other, with the opposite tothereofconcaved,the angular advance of said, gear-Wheel teeth beingadapted to rotatably drive the pinion about its axis and to prevent thegear-Wheels from being rotated by the pinion.

3, In dili'croutial gearing, a pinion, a pair of gear Wheels eachfixedly connected to Wheel-axles arranged in alinement, said pinionbeing in mesh With both said gear- Wheels and adapted to be rotated,about its axis by either gear-Wheel, the teeth of the pinion beingrounded at one end and pointed at the other, with the opposite facesthereof concaved, the teeth of said gear-Wheels having angular relationto the teeth of said pinion whereby the pinion in its axial revolutionis prevented from rotating the gear Wheels, and a housing carrying saidpinion through which rotary motion of the pinion imparted by onegear-Wheel is transmitted to the other gear-Wheel.

l. In difi'erent-ial gearing, a rotatable housing, means to rotate saidhousing, a pinion mounted for rotation in Said housing, a pair of alinedWheel-axles rotatively mounted axially of said housing, geai wheelsfixedly secured to the inner ends of said axles, said gear-Wheels havingrelatively opposed faces provided Withteeth of oppositely directedeonvolute configuration having angular pitch of relatively slightangular advance and terineshing upon opposite sides With the teeth 01'said pinion, the teeth of the pinion being rounded at one end andpointed at the other, with the opposite faces therleoi concavcd, wherebythe pinion may be rotated about its axis While the pinion is preventedfrom rotating the gear-Wheels except through the rotation of thehousing.

Signed at Seattle, Washington, this 19th day of November, 1915.

HARRY M. PATCH.

